1. Field of the Invention
The present invention relates to battery modules and charging modules. More particularly, the present invention relates to a thin battery module and a charging module capable of suppressing an increase in temperature of the battery in the battery module when the battery is being charged.
2. Description of Related Art
Secondary cells are used in electronic devices, such as mobile phones. The secondary cells can be used for a longer time through repetitive charging by chargers. For example, Japanese Unexamined Patent Application Publication No. 5-304728 describes a technology concerning a charger that charges a secondary cell. The charger includes a casing 1 on which a secondary cell 5 is detachably mounted and a charging circuit 4 included in the casing 1, as shown in FIG. 8, which illustrates an example of a charging module in related art. The charging circuit 4 includes a low heat circuit 2 and a high heat circuit 3. The low heat circuit 2 includes a noise canceling circuit and a primary rectifying circuit. The high heat circuit 3 includes an inverter circuit, a secondary rectifying circuit, and a charging control circuit.
The high heat circuit 3 is positioned farther apart from the secondary cell 5 than the low heat circuit 2. A heat insulation rib 11 vertically hanging from the top face of the casing 1 is provided between the low heat circuit 2 and the high heat circuit 3. The heat insulation rib 11 prevents air heated by the high heat circuit 3 from flowing toward the other side (i.e., lower side) of the casing 1 where the secondary cell 5 is located. Multiple air vents 10 are provided in the top and bottom faces of a portion in the casing 1, where the high heat circuit 3 is housed. The air heated by the high heat circuit 3 is externally discharged from the air vents 10. According to the above configuration, an increase in temperature of the secondary cell 5 during charging is suppressed, thus, preventing the performance of the secondary cell 5 from degrading.
However, the high heat circuit 3 is arranged at a location apart from the secondary cell in the charger disclosed in Japanese Unexamined Patent Application Publication No. 5-304728. Although it is possible to suppress an increase in temperature of the secondary cell 5 due to the high heat circuit 3 to prevent the performance of the cell from being degraded due to heat, the space in the charger is expanded because the high heat circuit 3 is spaced apart from the secondary cell 5 and, therefore, unnecessarily increases the size of the charger. In addition, since the insulation rib 11 is provided to prevent the air heated by the high heat circuit 3 from flowing from the space at the side of the high heat circuit 3 toward the secondary cell 5, there is a problem in that the structure of the casing 1 becomes complicated and, therefore, undesirably increases the manufacturing cost of the charger.